(i) Field of the Invention
This invention relates to a board-mounted optical connector of a type that is mounted on a board such as a back plane and used.
(ii) Description of the Related Art
In recent years, optical signal transmission has been conducted as a measure for the limit of the transmission rate of electric wires due to an increase in information communication speed and the occurrence of electric noise due to a decrease in the size of electronic equipment. In devices such as a router which handle enormous signal processing, a number of wires concentrate and cross one another on a back plane board. For optical wiring, a high-density and compact back plane board has not been achieved.
An example of the prior art that has intended to achieve higher density optical wiring is Japanese Patent Laid-Open Publication No. 121697/2003. FIG. 18 shows across section of a device according to the prior art. This optical connector 80 can be fitted to a corresponding optical connector 90. To facilitate the fitting, the optical connector 80 has guide portions 81a for guiding the corresponding optical connector 90, and the corresponding optical connector 90 has guide portions 81b that correspond to the guide portions 81a. When actually used, the optical connector 80 is placed upright on a back plane board 81 as shown in FIG. 18. In the optical connector 80 placed on the board 81, an optical fiber 82 which is partially laid on the top surface of the back plane board 81 and is bent near the optical connector 80 at nearly right angle R to the back plane board 81 is housed, thereby making it possible to mount the optical connector even with small package board pitches. According to such a constitution, higher density wiring can be achieved with the optical fiber 82, and a more compact optical back plane can be attained.
Although not necessarily clear from the drawing, the optical connector 80 is assembled in the following manner. That is, firstly, the optical fiber 82 with a ferrule 87 and a ferrule holder 86 attached to its front end is passed through a cylindrical housing 85 for the optical connector in advance, an optical fiber 82a is fixed at a predetermined position on the back plane 81, the optical fiber 82 which has been passed through the cylindrical housing 85 in advance is then pulled in the direction indicated by the arrow A in FIG. 18 so as to press-fit and fix the ferrule holder 86 and the ferrule 87 in the cylindrical interior of the cylindrical housing 85, and finally the cylindrical housing 85 is disposed at a predetermined position on the back plane 81.
However, when such an assembling method is used, the optical fiber 82 must be provided with an extra length since the optical fiber 82 is pulled later, and there is a high possibility that the optical fiber 82 may be broken while the cylindrical housing 85 and other optical connector components are fixed to the optical fiber 82 and they as a whole are then mounted at a predetermined position on the back plane 81. Further, for example, a fiber board which bundles a plurality of optical fibers 82 or such optical fibers has no rigidity around a portion where the optical fibers are taken out. Further, a number of connectors are attached to a single fiber board, thereby making the mounting process difficult. In addition, in high-density packaging which requires small package board pitches, when connectors are mounted on a back plane with the connectors connected to a fiber board, adjacent connectors interfere with each other, thereby making it difficult to mount the optical connectors on the back plane.
Patent Literature 1
Japanese Patent Laid-Open Publication No. 121697/2003
The present invention has been conceived to solve the above problems of the prior art. An object of the present invention is to provide an optical connector which enables high-density wiring of optical fibers without requiring the optical fibers to have an extra length and can be assembled easily by assembling the connector on a board, i.e. by carrying out positioning of optical fibers and a fiber board on a back plane and positioning of an optical connector housing on the back plane separately and then attaching the optical fibers and the fiber board to the optical connector housing.